Comparative Effects of Application of Coated and Non-Coated Urea in Clayey and Sandy Paddy Soil Microcosms Examined by the ^<15>N Tracer Technique : II. Effects on Soil Microbial Biomass N and Microbial ^<15>N Immobilization(Fertilizers and Soil Amendment

スポンサーリンク

概要

• 論文の詳細を見る

• Nitrogen fertilizer and soil types exert an impact on plant and soil microbial biomass (SMB). A ^<15>N tracer experiment was conducted to compare the effects of the application of controlled-release coated urea (CRCU) and urea on SMB in gley (clayey) and sandy paddy soils. The fertilizers were applied at the rate of 8 g N m^<-2> for CRCU as deep-side placement and 10 g N m^<-2> for urea mixed into soil or applied into floodwater. The soil type and soil layer (surface : few millimeter depth of surface soil to include benthic algae ; subsurface : 1 to 20 cm depth), but not the fertilizer type, affected the amount of microbial biomass N (B_N). On an area basis, subsurface soil layers contained about 2-3 times the amount of B_N in the surface layers. The seasonal average B_N amount i. e. at 1 to 20 cm depth, in the gley soil was 1.67 g N m^<-2>, compared to 1.20 g N m^<-2> for the sandy soil. The proportion of B_N in total soil N was significantly influenced by the soil type and soil layer, and was higher for the surface layers of both soils and subsurface layer of the sandy soil than for the subsurface layer of gley soil. Soil type, soil layer, and fertilizer type significantly influenced the amount of microbial biomass ^<15>N (B^<15N>). Unlike B_N, the amount of B^<15N> was significantly higher in the surface (11.9-177.3 mg N m^<-2>) than in the subsurface soil layers (4.8-83.6 mg N m^<-2>), especially with urea application between 60 and 120 DAT (days after transplanting). At 30 DAT, the subsurface layer of the sandy soil showed a higher B^<15N> (218 mg N m^<-2>) amount than the surface layer (133.4 mg N m^<-2>). Sandy soil (4.8-218 mg N m^<-2>) and urea (6.2-218 mg N m^<-2>) induced a larger increase of the amount of B^<15N> than the gley soil (6.2-83.6 mg N m^<-2>) and CRCU (4.8-40 mg N m^<-2>). Again, the sandy soil, surface soil layers, and urea induced a higher proportion (%) of B^<15N> in B_N than the gley soil, subsurface soil layers, and CRCU, respectively. The soil type affected B_N more than the fertilizer type, which showed only minimal differences. However, ^<15>N analysis revealed the existence of greater differences in the effects of CRCU and urea on the B^<15N> amount. Sandy soil and the application of urea led to a higher microbial N immobilization than the gley soil and CRCU application, respectively.

• 社団法人日本土壌肥料学会の論文

著者

• Inubushi Kazuyuki

  Laboratory of Soil Science, Faculty of Horticulture, Chiba University

• Acquaye Solomon

  Graduate School of Science and Technology, Chiba University

• Acquaye Solomon

  Graduate School Of Science And Technology Chiba University Soil Science Laboratory

• Inubushi Kazuyuki

  Laboratory Of Soil Science Faculty Of Horticulture Chiba University

関連論文

• Role of Microbial Biomass in Biogeochemical Processes in Paddy Soil Environments
• 6-10 Microbial activity and diversity in floodwater and surface soil layers of paddy fields under Free Air Carbon dioxide Enrichment (FACE)
• Comparative Effects of Application of Coated and Non-Coated Urea in Clayey and Sandy Paddy Soil Microcosms Examined by the ^N Tracer Technique : II. Effects on Soil Microbial Biomass N and Microbial ^N Immobilization(Fertilizers and Soil Amendment
• Comparative Effects of Application of Coated and Non-Coated Urea in Clayey and Sandy Paddy Soil Microcosms Examined by the ^N Tracer Technique : I. Effects on Growth, N Uptake, and Yield of Rice Crop(Fertilizers and Soil Amendments)
• Effects of slow release fertilizers on microbial biomass in submerged soil microcosms without plants(The Annual Meeting of the Society in 2001)

スポンサーリンク